[Association between extracellular water/body cell mass ratio and cognitive impairment in patients on maintenance hemodialysis]

Objective: To explore the correlation between extracellular water/body cell mass (ECW/BCM) ratio and cognitive impairment (CI) in patients on maintenance hemodialysis (MHD). Methods: A multicenter, cross-sectional study was conducted in Guizhou Province. All adult MHD patients in hemodialysis centers of 18 hospitals in Guizhou Province between June and October 2020 were included. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) score. The ECW and BCM was derived from bioelectrical impedance, and the ECW/BCM ratio was calculated. The patients were divided into four groups based on the quartile of ECW/BCM ratio. Multivariate logistic regression analysis and subgroup analysis were conducted. Results: A total of 3 160 patients were included in the final analysis, of which 761 (24.1%) developed CI. There were 1 868 males (59.1%) and 1 292 females (40.9%), and the mean age was (55±15) years. Multivariate logistic regression analysis showed that the risk of CI in ECW/BCM Q3 group was 1.55 times (95%CI: 1.03-2.34, P=0.035) of that in group Q1, while the risk of CI in Q4 group was 1.62 times of that in group Q1 (95%CI: 1.05-2.51, P=0.029). Subgroup analysis showed that there was an interaction between previous cerebrovascular event and ECW/BCM on CI (P for interaction=0.04). Patients with a previous history of cerebrovascular events had a higher risk of CI than those without. Among those with no previous cerebrovascular events, the risk of CI in group Q4 was 1.62 times of that in group Q1 (95%CI: 1.19-2.20), while the risk of CI in group Q4 was 7.17 times of that in group Q1 (95%CI: 1.59-32.35) in those with previous cerebrovascular events. Conclusion: Increased ECW/BCM ratio is associated with increased CI risk in patients with MHD, and the risk was more obvious in those with previous history of cerebrovascular events.